There's a good deal of overlap in the list. Carolina Christmas, for instance, is part of the larger North Carolina Digital Collections. Poke around a bit to see what's what, and check out the clip from the Louis Armstrong recording from his 1954 gig at the University of North Carolina.

The family records page includes marriage and death notices, cemetery listings, as well as an unusual collection of family Bible records.

You can search the complete NC Archives catalog, though there's no easy way I can see to limit your search to online-only materials.

Lastly, the NC Echo offers easy search access to multiple digital archives. In addition to those mentioned above, it also has content from what looks to be several hundred museums, libraries, schools, history groups and other resources across the state.

More historical archives and research materials can be found at these excellent resources: